America created the atomic bomb—or parts of it, at least—at the Y-12, X-10, and K-25 plants in this city northwest of Knoxville. Today, Oak Ridge and its plants are still an important component in the national defense industry.

Oak Ridge did not exist before 1942. When nuclear fission was discovered in the late 1930s, American scientists warned that this technology could be used to create a weapon more powerful than any known to man. As World War II escalated, and the United States joined the conflict in 1941, the U.S. military decided to exploit this technology.

Sites in New Mexico, Washington state, and East Tennessee were chosen for the work. The isolated hills in Tennessee were chosen because they were close to roads and rail lines, had ample supply of electricity, and because they would be hard for spies and curiosity-seekers to discover. Before the land was taken over by the government, about 3,000 people lived in homes that were scattered around the hills and valleys. Each homeowner received a letter stating that their land and home was being taken; and how much money they would receive in exchange.

Oak Ridge was built seemingly overnight. Between the spring of 1943 and the fall of 1944, the 59,000-acre tract of land bought for the project was developed into 10,000 homes and apartments, 13,000 dormitory spaces, 5,000 trailers, and more than 16,000 barracks. One of the facilities, K-25, where they processed uranium, was at the time the largest building in the world under one roof. Workers rode bicycles to get from one side of the massive structure to the other.

Tens of thousands of people came to live in Oak Ridge. Housing was in short supply, and African-American and some white workers were housed in drafty, leaky “hutments.” Social societies, schools, churches, theaters, barber shops, and much more were developed to entertain and meet the needs of the new residents.

When the United States dropped atomic bombs in Hiroshima and Nagasaki on August 6 and September 2, 1945, many workers at Oak Ridge learned for the first time what they had been doing all this time. Many were proud that they had helped to create the weapons that some believe ended World War II.

The end of the war did not mean the end of Oak Ridge. Y-12 continues to research, develop, and produce weapons for the U.S. military. In 1948 X-10 became the Oak Ridge National Laboratory, a center for science and research managed successively by the University of Chicago, Monsanto Chemical, Union Carbide, and Lockheed Martin corporations. It is now managed by the University of Tennessee and Battelle, and remains a center for scientific research in a wide range of fields.